sábado, 21 de mayo de 2011

Validez cuantitativa de un instrumento


Validez cuantitativa de un instrumento

1. Validez de contenido (Validez Cualitativa)
La validez de contenido intenta evaluar la capacidad del instrumento para recoger el contenido y el alcance del constructo. Podemos dividirlo en tres fases según el estado actual del conocimiento
a. Aproximación a la población (Validez de respuesta)
b. Juicio de expertos (Validación por jueces)
c. Revisión del conocimiento disponible (Validez racional)
2. Consistencia interna (Alfa de Cronbach)
Es la capacidad de obtener resultados independientes de las circunstancias accidentales de la medición. Se fundamenta en la varianza de la variable medida, existen varios índices que miden confiabilidad, entre ellos el Alfa de Cronbach y el Kuder-Richardson (KR-20). Es afectado por la heterogeneidad de los individuos evaluados; cuanto más heterogéneo es el grupo, mayor es el coeficiente de fiabilidad.
3. Validez de constructo (Rotación de Varimax)
Debemos establecer probabilísticamente grupos de ítems que deberán ser definidos como dimensiones. Estas dimensiones deben ser conceptualizadas de manera consensuada para otorgarles el carácter de útiles y científicamente válidos, por cuanto no existe una prueba patrón. Si los dominios se han construido teóricamente, la estadística corrobora la idoneidad de estas agrupaciones.
4. Criterio (Índice Kappa)
Cuando la variable medida cuenta con un Gold Standard, entonces se puede verificar los resultados hallados, mediante un procedimiento. Si el criterio se fija en el presente, se habla de validez concurrente (los resultados del instrumento se correlacionan con el criterio en el mismo momento o punto del tiempo). Si el criterio se fija en el futuro, se habla de validez predicativa.
5. Estabilidad (ANOVA)
La medición debe arrojar valores constantes siempre que sean tomadas en condiciones similares entre una medición y otra (test-retest). Se trata de ver, hasta qué punto un conjunto de medidas son reproducibles en el tiempo, el grado en que las puntuaciones son estables sería el grado de fiabilidad, propiedad que solo puede ser evaluada si un constructo está plenamente definido.
6. Rendimiento (Curvas ROC)
El objetivo es optimizar el instrumento para reducir el error a la hora de emitir juicios de valor para tomar decisiones. Se construye una curva en base a los pares ordenados de sensibilidad y 1-especificidad en distintos puntos de corte del instrumento. Debemos elegir el puto de corte que nos ofrezca los mayores valores de sensibilidad y especificidad a través de las Curvas de ROC.
Para descargar este audio haz click aquí

Movie Reviews


Lars von Trier in Mougins, France.
Guillaume Horcajuelo/European Pressphoto Agency
Lars von Trier in Mougins, France.
Lars von Trier says his newfound sobriety led to his fumbling performance at a Cannes Film Festival news conference that resulted in his expulsion from the festival.
Owen Wilson and Rachel McAdams in
Roger Arpajou/Sony Pictures Classics
Owen Wilson and Rachel McAdams in "Midnight in Paris."
Woody Allen, with the help of Paris and the ghosts of its famous dead, has found a credible blend of whimsy and wisdom.
Johnny Depp in
Peter Mountain/Walt Disney Pictures
Johnny Depp in "Pirates of the Caribbean: On Stranger Tides."
While this picture is called “On Stranger Tides,” it is by far the least strange of all the “Pirates” episodes so far.
Movie Reviews
MOVIE REVIEW | 'FLORENT: QUEEN OF THE MEAT MARKET'
Florent Morellet in

Florent, the Restaurant and the Man, on Film

High rents and changing times claimed the all-night restaurant and neighborhood landmark.
MOVIE REVIEW | 'LOUDER THAN A BOMB'
From left, Kevin Harris, Charles Smith, She'Kira McKnight and Jésus Lark of the Steinmenauts.

A Stream of Words, Painting a Picture

The documentary “Louder Than a Bomb” follows four teams of teenagers as they prepare for a high school poetry slam in Chicago.
MOVIE REVIEW | 'LOST BOHEMIA'

The Residents Go, the Music Stays

“Lost Bohemia,” Josef Astor’s documentary, chronicles the eviction of the last residents of Carnegie Hall Studios.
News & Features
“Moonstruck” (1987), with Cher and Nicolas Cage.

A Director of Ideas With Decades of Them

Norman Jewison, who has directed films like “Moonstruck” and “In the Heat of the Night,” will be the subject of a retrospective at the Film Society of Lincoln Center.
Cary Grant and Rosalind Russell, in “His Girl Friday,” a remake of “The FrontPage.”

Recycled Films and Bitsy Screens

A. O. Scott and Manohla Dargis take on questions about the value of movie remakes, finding the quality films at the local theater and more.
James Garner in “Grand Prix” (1966), which is now available on Blu-ray. The film, directed by John Frankenheimer, was shot in the 65-millimeter Super Panavision format.

Start Your High-Def Engines

“Grand Prix,” a John Frankenheimer film from 1966, isn’t great shakes as a movie, but the Blu-ray version is a beauty from a technical point of view.
The Maori-inspired tattoo on the face of Ed Helms's character is instantly recognizable as Mike Tyson's tattoo, which is part of the joke.

On Tyson’s Face, It’s Art. On Film, a Legal Issue.

A suit over Mike Tyson’s tattoo sported by a character in the movie “The Hangover Part II” could offer the first rulings on copyrighted works on people’s bodies.
Mary Hart and Andy Warhol in 1985.

After Hart, a Deluge of Meaner Celebrity TV?

Mary Hart, the “Entertainment Tonight” anchor, leaves the show on Friday after 29 years, during which she helped usher in a new celebrity television age.
CRITIC’S NOTEBOOK
Lars von Trier at the news conference for

A Provocateur Steals Cannes Spotlight

Cannes declared the Danish director Lars von Trier a persona non grata on Thursday, the same day as the premiere of “This Is Not a Film,” by Jafar Panahi.
CRITIC’S NOTEBOOK
A scene from

Bucking Up the British in the Midst of the Fight

“Went the Day Well?” is an undeservedly forgotten British film made in 1942 that was intended to lift the spirits of the English-speaking world in the fight against Hitler.

A 2012 Release Date Is Set for a ‘Titanic’ in 3-D

In case you ever doubted it, James Cameron is truly the king of the three-dimensional world.
Lars von Trier and the actress Kirsten Dunst at the news conference for

Danish Director Barred From Festival After Making Hitler Jokes

The Danish filmmaker was banished from Cannes after remarks at a news conference.
Carey Mulligan on the set of “Through a Glass Darkly.”

Postgraduate Work in Bergman Madness

Carey Mulligan has embarked on an eight-week run in the Atlantic Theater Company’s production of “Through a Glass Darkly,” Jenny Worton’s stage adaptation of the 1961 Ingmar Bergman film.
ARTS & LEISURE
The screenwriter Paddy Chayefsky(1923-1981) won an Academy Award for his jeremiad “Network” (1976), starring Faye Dunaway.

Notes of a Screenwriter, Mad as Hell

The screenwriter Paddy Chayefsky left behind a large cache of his notes for his incendiary, Oscar-winning script for “Network.”
Arnold Schwarzenegger making a speech in 2010. His next movie, which is expected to begin shooting in late August, is titled “Cry Macho.”

Schwarzenegger’s Next Film May Have a Familiar Plot

Arnold Schwarzenegger’s next film, “Cry Macho,” is expected to have some parallels to his recent personal revelations.
Bruce Ricker in 2002.

Bruce Ricker, Who Made Jazz Documentaries, Is Dead at 68

Mr. Ricker made jazz resoundingly visible in a series of highly regarded documentaries, including “The Last of the Blue Devils.”
ARTSBEAT
Brad Pitt Discusses ‘The Tree of Life’

Brad Pitt Discusses ‘The Tree of Life’

Brad Pitt spoke about “The Tree of Life” and Terrence Malick in an interview in Cannes on Tuesday.
Brad Pitt and Laramie Eppler in

Pursuing Imperfection in Malick’s Eden

With his new film “The Tree of Life,” the reclusive filmmaker Terrence Malick provides exactly what Cannes thrives on: mystique and anticipation.